Metal-Oxygen Primary Reserve Batteries for Munitions and the Like Applications

ABSTRACT

A metal-gas battery including: a battery core, gas container and a movable member. The battery core including a metal anode; a non-aqueous electrolyte; a porous cathode; and terminals for providing electrical power from the battery core. The gas container being configured to hold a pressurized gas. The movable member being configured to be movable from a non-activated position in which the pressurized gas in the container is sealed from entering the porous cathode and an activated position in which the pressurized gas flows into the porous cathode to activate the battery core.

CROSS-REFERNCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.63/064,325, filed on Aug. 11, 2020, the entire contents of which isincorporated herein by reference.

BACKGROUND Field

The present invention relates generally to reserve power sources formunitions and other similar applications; and more particularly toLithium-oxygen reserve batteries and methods of their activation for usein gun-fired munitions, sub-munitions, mortars, and the like. TheLithium-oxygen batteries may be activated and deactivated as required tosatisfy the system power requirement and to maximize the power sourcerun time.

Prior Art

Reserve batteries of the electrochemical type are well known in the artfor a variety of uses where storage time before use is extremely long.Reserve batteries are in use in applications such as batteries forgun-fired munitions including guided and smart, mortars, fusing mines,missiles, and many other military and commercial applications. Theelectrochemical reserve-type batteries can in general be divided intotwo different basic types.

The first type includes the so-called thermal batteries, which are tooperate at high temperatures. Unlike liquid reserve batteries, inthermal batteries the electrolyte is already in the cells and thereforedoes not require a release and distribution mechanism such as spinning.The electrolyte is dry, solid and non-conductive, thereby leaving thebattery in a non-operational and inert condition. These batteriesincorporate pyrotechnic heat sources to melt the electrolyte just priorto use in order to make them electrically conductive and thereby makingthe battery active. The most common internal pyrotechnic is a blend ofFe and KClO₄. Thermal batteries utilize a molten salt to serve as theelectrolyte upon activation. The electrolytes are usually mixtures ofalkali-halide salts and are used with the Li(Si)/FeS₂ or Li(Si)/CoS₂couples. Some batteries also employ anodes of Li(Al) in place of theLi(Si) anodes. Insulation and internal heat sinks are used to maintainthe electrolyte in its molten and conductive condition during the timeof use.

The second type includes the so-called liquid reserve batteries in whichthe electrodes are fully assembled for cooperation, but the liquidelectrolyte is held in reserve in a separate container until thebatteries are desired to be activated. In these types of batteries,since there is no consumption of the electrodes under thesecircumstances, the shelf life of the batteries is essentially unlimited.The battery is activated by transferring the electrolyte from itscontainer to the battery electrode compartment (hereinafter referred toas the “battery cell”).

A typical liquid reserve battery is kept inert during storage by keepingthe aqueous electrolyte separate in a glass or metal ampoule or in aseparate compartment inside the battery case. The electrolytecompartment may also be separated from the electrode compartment by amembrane or the like. Prior to use, the battery is activated by breakingthe ampoule or puncturing the membrane allowing the electrolyte to floodthe electrodes. The breaking of the ampoule or the puncturing of themembrane is achieved either mechanically using certain mechanisms or bythe high-G firing setback shock. In these batteries, the projectile spinor a wicking action of the separator is generally used to transport theelectrolyte into the battery cells.

In recent years, there have been a number of advancements in reservebattery technologies. Among these advances are superhydrophobicnanostructured materials, bimodal lithium reserve battery, and ceramicfiber separator for thermal batteries. In one liquid reserve batterytechnology under development, “superhydrophobic nanostructured material”is used in a honeycomb structure to keep the electrolyte separated fromthe battery cell. “Electrowetting” is achieved by the application of atrigger voltage pulse. The electrolyte can then penetrate the honeycombstructure and come into contact with the electrodes, thereby making thecell electrochemically active.

The currently available liquid reserve and thermal batteries of alltypes and configurations and those that are known to be underdevelopment suffer from several basic shortcomings for many current andfuture munitions applications, including the following:

-   -   1. The main shortcoming of currently available liquid reserve        batteries of all types and configurations is their very poor        performance at low temperatures, usually below −25 deg. F and        for becoming almost non-functional at lower temperatures. In        most munition applications, however, the batteries are required        to be operational at significantly lower temperatures of −40        deg. F and sometimes lower, and sometimes after storage at        temperatures as low as −65 deg. F.    -   2. Another shortcoming of all currently available liquid reserve        batteries is activation at very low temperatures.    -   3. Another shortcoming of all currently available liquid reserve        batteries is their relatively slow rise time, particularly at        low temperatures. Researchers have, however, attempted to        minimize this shortcoming by, for example, by injecting        pressurized electrolyte into the battery cells; using wicks to        increase the electrolyte diffusion rate; utilize spin and/or        setback to move electrolyte into the battery cell to increase;        etc. These methods have improved the liquid reserve battery rise        time to but not significantly enough to address all applications        and in many applications such solutions are not even practical.    -   4. Thermal reserve batteries do not have low temperature issues        and can be activated and produce power at even below −100        deg. F. However, thermal batteries have very short run time,        particularly for smaller sizes that are required in gun-fired        munitions in which the run time might become even less than one        minute.    -   5. Currently available liquid reserve and thermal reserve        batteries have both the shortcoming of not being able to be        reverted to their reserve state once they have been activated.        This capability is highly desirable for many munitions and other        emergency powering applications in which different amounts of        electrical power may be needed at different times with periods        in between, which might be very long, during which no power is        needed.

In current lithium metal-based liquid reserve batteries, such as lithiumthionyl chloride and lithium graphite fluoride, rely on the supply of aliquid electrolyte to the cathode electrode at the time of activation.This requires the storage of the liquid electrolyte separately from therest of the battery mostly inside glass ampoules, which are broken inthe process of activation. The liquid electrolytes have also been storedin metal bellows with provided membranes or have been separated from thebattery core by certain membranes, which in either case is rupturedduring the activation process. In general, the activation process isrelatively slow, resulting in relatively slow power rise time, and facedistribution issues inside the battery core, particularly at lowtemperatures.

There are only a few battery chemistries that have the potential chanceof achieving significantly higher energy density than is currentlyavailable for reserve batteries. The main candidates for achievingsignificantly higher energy density for reserve batteries are metal-airbased battery systems, FIG. 1. The most common type of commercialmetal-air battery utilizes zinc-air chemistry and has a practicalspecific energy of ˜370 Wh/kg, while this battery chemistry has atheoretical specific energy of 1350 Wh/kg. In addition to zinc-airbatteries, aluminum-air batteries are also available in the commercialmarket, although only in a limited fashion. Aluminum-air batteries havea much greater theoretical specific energy (8140 Wh/kg) and althoughthey currently have a practical specific energy of ˜350 Wh/kg but havethe potential for significant specific energy improvement. The highesttheoretical specific energy for a metal-air battery chemistry islithium-air at 11,500 Wh/kg giving it and aluminum-air batteries thebest potential to realize significantly higher specific energy valuesfor reserve batteries as compare to the currently available reservebatteries.

In a primary Metal-Oxygen battery, oxygen gas reacts with the metal ionson the porous carbon substrate cathode. There is a clear advantage ofMetal-Oxygen batteries over traditional liquid primary reserve batteriesin that the activation mechanism of the former does not require theinjection of a liquid electrolyte but of oxygen gas. While Metal-Oxygenbatteries do still require of a liquid electrolyte to transport themetal ions from the metal anode to the cathode electrode during batterydischarge, the liquid electrolyte on its own does not activate thebattery and hence it can then be added to the battery during theassembly process. Since the activation of the battery relies on thetransport of a gas, and not of a liquid, into the porous cathodematerial, the rate of activation for Metal-Oxygen batteries is muchfaster and more efficient than that of the traditional liquid reservebatteries. If the metal used in the battery is lithium, and since thetheoretical energy density of Li-Oxygen batteries is the highest of alllithium metal batteries (11,500 Wh/kg of lithium, excluding the oxygenmass), therefore primary reserve Li-Oxygen batteries have the potentialto be significantly more energy dense than the traditional liquidreserve batteries.

A primary reserve battery based on Metal-Oxygen chemistry is activatedby allowing oxygen gas to enter the porous cathode material. The metalin the battery can be one of those indicated in FIG. 1 and more, i.e.,lithium, sodium, potassium zinc, magnesium, calcium, aluminum, iron,silicon, germanium, and tin.

A lithium-air battery has three main components: an anode, anelectrolyte, and a cathode, FIG. 2. The anode is the source oflithium-ions and can be lithium metal. The electrolytes can be e.g.,aqueous, aprotic (organic), mixed aqueous/aprotic, or solid state, eachhaving its own advantages and disadvantages. The lithium-air batteryalso includes the cathode, which as is stated in the name of thistechnology, is air—or more accurately stated, the oxygen in the air.Being that the cathode materials is supplied by the oxygen in the airthe mass of the cathode is very small, thus imparting a significantsavings in the mass of the overall system and the theoretical specificenergy. However, the oxygen still needs a platform for theelectrochemical reactions of the battery to take place. These reactionscan be supported by the use of porous carbon materials that are in somecases coated with a catalytic metal oxide, such as MnO₂ or CoO₂.

Reserve Lithium-air batteries are primary batteries. In general, thelithium air battery includes a lithium metal anode electrode capable ofgenerating lithium ions during discharge and a cathode containing oxygenin the air as a cathode active material, and a lithium ion conductivemedium (electrolyte) is provided between the cathode and anode. Thelithium air primary battery has a theoretical energy density of 3000Wh/kg or more, which corresponds to about 10 times energy density of alithium ion battery. In addition, the lithium air battery may beeco-friendly and provide improved stability as compared to the lithiumion battery.

SUMMARY

Therefore, reserve batteries based on Lithium-air battery operationmechanism would provide significantly higher energy density than isavailable from all current liquid reserve batteries. Such reservebatteries must, however, be suitable for use in gun-fired and othermunitions, for example, should be capable of withstanding high firingshock loadings and have shelf life of over 20 years.

It is also highly desirable that such higher density reserve batteriesbe capable of being activated and deactivated, i.e., reverted to itsreserve state, in order to significantly increase the run time of thebattery when the power demand varies significantly over time,particularly when for very long periods of times very small or no powermay be needed for the battery to provide.

A need therefore exists for reserve batteries that can provideelectrical energy to munitions for relatively long run time that iscurrently possible with thermal batteries and liquid reserve batteries.

A need also exists for reserve batteries that can be activated anddeactivated and reverted to their pre-activation reserve state.

In particular, there is a need for reserve batteries with shelf life ofover 20 years that can provide power to low power electronics over longperiods of times that could extend for days, weeks and even months. Itis appreciated by those skilled in the art that to achieve such longshelf life, the battery components can be hermetically sealed inside thereserve battery housing.

A need also exists for reserve batteries with significantly higherenergy density that the currently available reserve batteries.

A need also exists for reserve batteries that can be activated veryrapidly to provide electrical energy.

Such reserve batteries can be initiated as a result of the munitionsfiring using inertial igniters, such as those disclosed in U.S. Pat.Nos. 7,437,995; 7,587,979; 7,587,980; 7,832,335 and 8,061,271 and U.S.patent application Ser. Nos. 12/774,324; 12/794,763; 12/835,709;13/180,469; 13/207,280 and 61/551,405, the full disclosure of each ofwhich being incorporated herein by reference, or piezoelectric-basedinertial igniters, such as those disclosed in U.S. Pat. No. 8,024,469and U.S. patent application Ser. Nos. 13/186,456 and 13/207,355, thefull disclosure of each of which being incorporated herein by reference)or other electrical initiators. The piezoelectric-based inertialigniters, such as those that can provide relatively long initiationdelay, can delay or eliminate the time period in which the battery issubjected to high acceleration/deceleration levels. The reserve batterymay also be activated following launch when its power is needed, whichmay in certain cases be long after launch and even after landing. Theinitiation devices to be used can also be configured to operate safelyby differentiating all-fire and various no-fire events, such asaccidental drops and vibration and impact during transportation andloading and even nearby explosions. The task of differentiating all-fireconditions from no-fire conditions can be performed without the use ofexternal acceleration sensors and the like, and/or the use of externalpower sources.

An objective is to provide new types of reserve batteries (powersources) that can operate efficiently at low temperatures and that canbe activated and brought to operational power levels rapidly. Suchreserve batteries can also be fabricated in small sizes suitable for usein small and medium caliber munitions, sub-munitions and the like.

Another objective is to provide new types of reserve batteries that canbe activated and deactivated, i.e., reverted to their reserve batterystate, as needed for powering the intended electrical energy consumingdevices.

Another objective is to provide new types of reserve batteries andmethods of providing smart and programmable power systems that canmaximize the overall efficiency of the power system and thereby minimizethe total volume of the power system, such as for munitionsapplications.

Another objective is to provide new types of reserve batteries that canbe rapidly activated using electrical or inertial activation devices toprovide electrical energy as needed and become deactivated, i.e., bereverted to its reserve state, when it does not have to provideelectrical energy, to extend its useful service period of time as muchas possible.

To ensure safety and reliability, the reserve batteries can withstandand not initiate during acceleration events which may occur duringmanufacture, assembly, handling, transport, accidental drops, etc.Additionally, once under the influence of an acceleration profileindicating firing of the ordinance, i.e., an all-fire condition (with orwithout a programmed delay period), the reserve battery should initiatewith high reliability.

The disclosed reserve power sources can be provided with hermeticallysealed packaging. As such, the disclosed reserve power sources would becapable of readily satisfying most munitions requirement of 20-yearshelf life requirement and operation over the military temperature rangeof −65 to 165 degrees F., while withstanding high G firingaccelerations.

In many applications, the reserve battery can provide full or close tofull power very short time after initiation. This capability can bechallenging when the reserve battery is at very low temperatures, suchas the aforementioned −65 degrees F.

There is a clear advantage for the development of reserve batteries thatcan use Lithium-air primary battery technologies over liquid reservebatteries and thermal batteries as was previously described. For thecase of liquid reserve batteries, the main advantages include theelimination of separate liquid electrolyte storage and a significantincrease in the amount of electrical energy that can become availableper unit volume, which are of particular importance in applications suchas munitions. While Li-Air batteries may still require a liquidelectrolyte to transport the lithium ions from the lithium metal anodeto the cathode electrode during battery discharge, the liquidelectrolyte on its own does not activate the battery and hence it canthen be added to the battery during the battery assembly process. Inaddition, since activation of the battery relies on the transport of agas and not of a liquid into the porous cathode material, the rate ofactivation for Li-Air batteries is much faster and efficient than thatof the traditional liquid reserve batteries. Moreover, since thetheoretical energy density of Li-Air batteries is the highest of alllithium metal batteries, Li-Air based reserve batteries have thepotential to be capable of providing significantly more electricalenergy than currently available liquid reserve batteries can provide.

Accordingly, methods and apparatus are provided for reserve batteriesthat are based on Lithium-Air technology and have long shelf life ofover 20 years.

Furthermore, methods and apparatus are provided for reserve batteriesthat can be activated and deactivated and reverted to their reservestate on command or via a self-regulated mechanism.

Furthermore, methods and apparatus are provided for activation ofreserve batteries when subjected to a prescribed gun or the like firingaccelerations as described by a shock loading level and its duration andthat it does not activate under prescribed accidental shock loadingssuch as drop over hard surfaces or due to transportation vibration andother similar (non-activation) events.

Furthermore, methods and apparatus are provided for activation ofreserve batteries based on external commands, which can be initiatedbased on a pre-programmed plan or a sensory or certain event detectionor the like.

It is appreciated by those skilled in the art that since Lithium-Oxygenbatteries has the potential of providing reserve batteries with thehighest energy density, hereinafter the different embodiments aredescribed herein in terms of Lithium-Oxygen reserve batteries withoutany intention of limiting the disclosed embodiments to Lithium metal andin general, any other metal, including those disclosed above may be usedto replace the Lithium metal as the anode.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus ofthe present invention will become better understood with regard to thefollowing description, appended claims, and accompanying drawings where:

FIG. 1 illustrates theoretical specific energies of various metals knownin the prior art which can be used in metal-air battery technology.

FIG. 2 illustrates basic components of a Lithium-Air battery of theprior art.

FIG. 3 illustrates a cross-sectional view of a first embodiment of theLithium-Oxygen reserve battery.

FIG. 4 illustrates a cross-sectional view of an alternative activationmechanism assembly in the Lithium-Oxygen reserve battery embodiment ofFIG. 3.

FIG. 5 illustrates a cross-sectional view of another embodiment of aLithium-Oxygen reserve battery configured for activation manually orusing an externally positioned actuation device.

FIG. 6 illustrates a cross-sectional view of an alternative activationmechanism assembly of the embodiment of FIG. 5 in the Lithium-Oxygenreserve battery core.

FIG. 7 illustrates a cross-sectional view of an embodiment ofLithium-Oxygen reserve battery configured to allow activation anddeactivation of the reserve battery manually or via an externallypositioned actuation device.

FIG. 8 illustrates a blow-up view “A” of FIG. 7 showing details of onemechanism for activating and deactivating the reserve battery.

FIGS. 8A and 8B illustrate a method of providing the Lithium-Oxygenreserve batteries with external bellow activation mechanisms with“safety pin” to prevent for accidental activation.

FIG. 9 illustrates a cross-sectional view of another embodiment ofLithium-Oxygen reserve battery configured to be activated when subjectedto a prescribed acceleration profile.

FIG. 10 illustrates a cross-sectional view of another embodiment ofLithium-oxygen reserve battery configured for an initial activation whensubjected to a prescribed acceleration profile and for consequentactivation/deactivation on command.

FIG. 11 illustrates a cross-sectional view of another embodiment ofLithium-oxygen reserve battery that can be initially activatedinertially when subjected to a prescribed acceleration profile or fromexternal power and for consequent activation/deactivation on command.

FIG. 12 illustrates a cross-sectional view of another embodiment ofLithium-oxygen reserve battery configured for user mountedactivation/deactivation on command.

FIG. 13A illustrates a blow-up view “B” of the oxygen gas valve of theLithium-oxygen reserve battery embodiment of FIG. 12.

FIG. 13B illustrates an alternative oxygen gas valve for theLithium-oxygen reserve battery embodiment blow-up “B” of FIG. 12configured for activation when subjected to a prescribed accelerationprofile and staying activated.

FIG. 13C illustrates an alternative oxygen gas valve for theLithium-oxygen reserve battery embodiment blow-up “B” of FIG. 12configured for activation when subjected to a prescribed accelerationprofile and be activated and deactivated and/or stay activated oncommand.

FIG. 14 illustrates a cross-sectional view of another embodiment ofLithium-oxygen reserve battery configured for activation by initiationof a pyrotechnic charge that is ignited electrically.

FIG. 15 illustrates a cross-sectional view of an example of a modifiedactivation mechanism for the embodiment of FIG. 7.

FIG. 16 illustrates a cross-sectional view of another embodiment ofLithium-oxygen reserve battery configured for activation when subjectedto a prescribed acceleration profile.

DETAILED DESCRIPTION

The present Li-Oxygen reserve batteries are described using the basicLi-Oxygen reserve battery embodiment 10 shown in the cross-sectionalschematic of FIG. 2. As discussed above, such Li-Oxygen reserve batteryis presented by way of example and without any intention of limiting thedisclosed embodiments to Lithium metal and in general, any other metal,including those disclosed above may be used to replace the Lithium metalas the anode.

As can be seen in FIG. 3, the reserve battery embodiment 10 comprises ametal anode, such as a Lithium metal electrode that is separated fromthe battery non-aqueous electrolyte by a Solid Electrolyte Interphase(SEI) layer. A porous cathode, such as a Carbon-based O₂ cathode is thenext component of the battery core into which a gas such as Oxygen gasor a gas containing Oxygen can be allowed to enter to activate thereserve battery. The above components of the Li-Oxygen reserve batteryare packaged inside a sealed housing 11. To achieve a hermeticallysealed reserve battery with a shelf life of over 20 years, the batteryterminals 12 can be provided with glass or other similar electricalinsulation as they pass through the sealed housing 11.

In another sealed housing compartment 18, oxygen gas is provided underpressure as shown in FIG. 3. The sealed compartment 18 and the batterycore housing 11 can share a common wall 19. The common wall 19 can beprovided with a relatively small opening 14 into the battery core, whichcan be sealed by a metallic diaphragm 13. In general, the housings 11and 18 can be formed from stainless steel and the diaphragm 13 can alsobe a thin stainless sheet that is welded to the wall 19.

Also provided inside the oxygen gas compartment 18 is a movable massmember 15, which can be biased firmly against surface 21 of thecompartment 18, such as, by a preloaded compressive spring 16. The massmember 15 can be provided with a sharp cutting member 17, which ispositioned above the hole 14.

The Li-Oxygen reserve battery embodiment 10 operates as follows. Innormal conditions, the diaphragm 13 prevents oxygen gas from enteringthe porous carbon-based O₂ cathode of the battery core. If the device towhich the reserve battery 10 is attached is accelerated in the directionof arrow 22, the acceleration would act on the mass member 15,generating a downward dynamic force. The compressive spring 16 ispreloaded such that when the acceleration in the direction of the arrow22 has reached a prescribed threshold, then the generated dynamic forcewould overcome the spring preload and the mass member 15 would begin tomove downward towards the diaphragm 13. If the acceleration in thedirection of the arrow 22 is long enough in duration, the mass member 15would gain enough speed for the cutting member 17 to reach the diaphragm13 and rupture it, thereby allowing the oxygen gas to begin to flow intothe porous carbon-based O₂ cathode section of the battery core andactivate the reserve battery. If the duration of the appliedacceleration in the direction of the arrow 22 is very short, for exampledue to accidental drop of the object to which the reserve battery 10 isattached, the mass member 15 and spring 16 system is configured suchthat the cutting member 17 is not displaced down enough to rupture thediaphragm 13.

In the schematic of FIG. 3 only one inertia-based activation mechanismis shown to be provided. It is appreciated that when a larger amount ofgas flow is desired, more than one activation mechanism of this type oranother type and corresponding hole 14 and diaphragm 13 may also beprovided.

It is appreciated by those skilled in the art that gases present in air,such as nitrogen, water vapor, and carbon dioxide can react with themetal anode, liquid electrolyte, and cathode electrode and negativelyimpact the discharge performance of currently available Lithium-Airbatteries. In addition, it has been extensively reported (for example,J. Read, K. Mutolo, M. Ervin, W. Behl, J. Wolfenstine, A. Driedger andD. Foster, “Oxygen Transport Properties of Organic Electrolytes andPerformance of Lithium/Oxygen Battery,” Journal of ElectrochemicalSociety, vol. 150, no. 10, pp. A1351-A1356, 2003) that a higher oxygenpartial pressure improves battery capacity, especially at high dischargerates, by increasing the oxygen saturation concentration in the liquidelectrolyte and by enhancing the oxygen diffusion rates in the porouscathode active sites. Therefore, pure oxygen can be used in thecompartment 18 to activate and discharge the battery.

The reserve battery embodiment 10 of FIG. 1 is assembled in the inactivestate with the pressurized oxygen in the adjacent compartment 18. As aresult, as long as oxygen gas is not allowed to enter the battery corethrough the provided hole 14 by the diaphragm 13, the battery stays inits inactive state, thus serving as a reserve battery. Once thediaphragm 13 has been ruptured as was previously described, the presenceof oxygen immediately starts the reduction/oxidation reactions insidethe battery core and, as a result, a voltage differential is establishedacross the anode and cathode sides of the cell. In the porous carboncathode electrode, oxygen is reduced to lithium peroxide thataccumulates in the pores of the electrode. At the same time, lithiummetal from the anode electrode is oxidized to lithium ions, whichtransport to the cathode electrode through the liquid electrolyte andpolymeric separator to the porous carbon cathode electrode. The batterydischarge reactions will continue until all the stored oxygen or theavailable Li metal is consumed.

In the Lithium-Oxygen embodiment 10 of FIG. 3, the mass-spring basedinertial activation mechanism of the battery is positioned inside thepressurized oxygen comportment of the battery. An alternativepositioning of the mass-spring inertial based activation mechanisminside the porous carbon-based O₂ cathode side of the reserve batteryassembly is shown in the cross-sectional view of FIG. 4 and indicated asthe reserve battery embodiment 20. In the schematic of FIG. 4, all othercomponents of the reserve battery are similar to that of the embodiment10 of FIG. 3. It is appreciated that to support the preloadedcompressive spring 24 of the mass-spring based inertial activationmechanism, a support structure 23, for example a beam structure 23 or abase support structure 25 must be provided.

One advantage of locating the mass-spring based inertial activationmechanism inside the battery core may be that it makes the batteryassembly easier and allows more space for the pressurized oxygen.

The Li-Oxygen reserve battery embodiment 20 of FIG. 4 operates asfollows. In normal conditions, the diaphragm 13 prevents oxygen gas fromentering the porous carbon-based O₂ cathode of the battery core. If thedevice to which the reserve battery 20 is attached is accelerated in thedirection of the arrow 26, the acceleration would act on the mass member27, which is movable within the housing 11, generating a downwarddynamic force. The compressive spring 24 is preloaded such that when theacceleration in the direction of the arrow 26 has reached a prescribedthreshold, then the generated dynamic force would overcome the springpreload and the mass member 27 would begin to move upward as viewed inFIG. 4 and towards the diaphragm 13. If the acceleration in thedirection of the arrow 26 is long enough in duration, the mass member 27would gain enough speed for the cutting member 28 to reach the diaphragm13 and rupture it, thereby allowing the oxygen gas to begin to flow intothe porous carbon-based O₂ cathode section of the battery core andactivate the reserve battery. If the duration of the appliedacceleration in the direction of the arrow 26 is very short, for exampledue to accidental drop of the object to which the reserve battery 20 isattached, the mass member 27 and spring 24 system is configured suchthat the cutting member 28 is not displaced up enough to rupture thatdiaphragm 13.

The Lithium-Oxygen reserve battery embodiments 10 and 20 of FIGS. 3 and4, respectively, are configured to be activated when the device to whichthey are attached is subjected to a prescribed acceleration profile,such as firing of a gun. In certain applications, however, the reservebattery is required to be activated manually or via certain actuationdevice that is positioned external to the reserve battery. The reservebattery embodiment 30 of FIG. 5 is configured to allow for activationmanually or using an external positioned actuation device.

In the schematic of FIG. 5, all other components of the reserve batteryare similar to that of the embodiment 10 of FIG. 3, except that itsmass-spring inertial activation mechanism is removed and is replaced bya mechanism that allows for manual activation or using an externallypositioned actuation device as described below.

As can be seen in FIG. 5, the Lithium-Oxygen reserve battery embodiment30 is provided with an activation mechanism comprising a metallic bellow31, such as that formed with the same metal with which the container 18is constructed, such as stainless steel. The bellow 31 is fixedlyattached to the top surface of the oxygen gas container 18, such as bywelding or brazing, and the attachment is tested to ensure that is fullysealed. The bellow is configured to have the required flexibility sothat when pressed to activate the battery as described below, it wouldessentially act as a spring element and return to its normal state. Thebellow is provided with a sealed cap 33, which may be integral to thebellow 31. A pin 34 is fixedly attached to the cap 33 of the bellow 31,which can be provided with a guide 36 inside the oxygen gas container 18as can be seen in FIG. 5. The pin 34 is provided with a sharp tip 35,which is positioned over the hole 14 and proximate to the diaphragm 13.

The Li-Oxygen reserve battery embodiment 30 of FIG. 5 operates asfollows. In normal conditions, the diaphragm 13 prevents oxygen gas fromentering the porous carbon-based O₂ cathode of the battery core. Theuser then may manually press the cap 33 of the bellow 31 down in thedirection of the arrow 37. As a result, the bellow 31 begins to deform,allowing the pin 34 to slide down the guide 36, causing the sharp tip 35of the pin 34 to rupture the diaphragm 13, thereby allowing the oxygengas to begin to flow into the porous carbon-based O₂ cathode section ofthe battery core and activate the reserve battery. It is appreciated bythose skilled in the art that the cap 33 of the bellow 31 may also bedisplaced down by an externally positioned linear or rotary electrical,piezoelectric-based or pneumatic or the like actuation device oncommand, for example provided by a system control system, as is wellknown in the art.

In the Lithium-Oxygen embodiment 30 of FIG. 5, the manual or externallyactuated activation mechanism of the battery is positioned at thepressurized oxygen comportment of the battery and must therefore becapable of withstanding the oxygen gas pressure while staying fullysealed. An alternative positioning of the activation mechanism is insidethe porous carbon-based O₂ cathode side of the reserve battery assemblyas shown in the cross-sectional view of FIG. 6. The resultingLithium-Oxygen reserve battery is indicated as the embodiment 40. In theschematic of FIG. 6, all other components of the reserve battery aresimilar to that of the embodiment 10 of FIG. 3. Another advantage oflocating the activation mechanism inside the battery core is that itmakes the battery assembly easier and allows more space for thepressurized oxygen.

As can be seen in FIG. 6, the Lithium-Oxygen reserve battery embodiment40 is provided with an activation mechanism that comprises a metallicbellow 41, such as being formed of the same metal with which the batterycore housing 11 is constructed, such as stainless steel. The bellow 41is fixedly attached to the side surface of the battery core housing 11,such as by welding or brazing, and the attachment is tested to ensurethat is fully sealed. The bellow 41 is provided with a sealed cap 42,which may be integral to the bellow 41. A pin 43 is fixedly attached tothe cap 42 of the bellow 41, which can be provided with a guide 44inside the battery core housing 11 as can be seen in FIG. 6. The pin 43is provided with an enlarged frontal section 45 that is movable withinthe housing 11 and that is close or in contact with the flexible member46 that bends as a bending flexure or rotates about a joint and on whichis provided a sharp tip member 47, which is positioned under the hole 49and proximate to the diaphragm 48 as can be seen in FIG. 6.

The Li-Oxygen reserve battery embodiment 40 of FIG. 6 operates asfollows. In normal conditions, the diaphragm 48 prevents oxygen gas fromentering the porous carbon-based O₂ cathode of the battery core. Theuser then may manually press the cap 42 of the bellow 41 in thedirection of the arrow 51. As a result, the bellow 41 begins to deform,allowing the pin 43 to slide in the guide 44, causing the sharp tip 45of the pin 43 to bend/rotate the member 46 upward towards the diaphragm48, thereby causing the sharp tip member 47 to rupture the diaphragm 48,thereby allowing the oxygen gas to begin to flow into the porouscarbon-based O₂ cathode section of the battery core and activate thereserve battery. It is appreciated by those skilled in the art that thecap 42 of the bellow 41 may also be displaced down by an externallypositioned linear or rotary electrical or piezoelectric-based orpneumatic or the like actuation device on command, for example providedby a system control system, as is well known in the art.

It is appreciated that once the novel Lithium-Oxygen reserve batteryembodiments of FIGS. 3-6 are activated, they would generally stayactivated until it runs out of either oxygen gas or Lithium metal. Inmany applications in which electrical energy may only be needed forrelatively short periods of times and relatively long enough times inbetween, then it is highly desirable for a reserve battery to be capableof being activated only when needed and then be deactivated, i.e.,reverted to its reserve battery state. The reserve batteries are hereindescribed as if it is implemented in the Lithium-oxygen reserve batteryembodiment 50 of FIG. 7.

In the schematic of FIG. 7, all components of the Lithium-oxygen reservebattery are similar to that of the embodiment 10 of FIG. 3, except thatits mass-spring inertial activation mechanism is removed and is replacedby the activation/deactivation mechanism shown in the blow-up view “A”,which is illustrated in detail in FIG. 8.

As can be seen in the blow-up view “A” of FIG. 8, the Lithium-Oxygenreserve battery embodiment 50 is provided with an activation mechanismcomprising two components. The first component is the actuationmechanism that comprises a metallic bellow 52, that can be formed of thesame metal with which the battery core housing 11 (FIG. 7) isconstructed, such as stainless steel. The bellow 52 is fixedly attachedto the side surface of the battery core housing 11, such as by weldingor brazing, and the attachment is tested to ensure that is fully sealed.The bellow 52 is provided with a sealed cap 53, which may be integral tothe bellow 52. A pin 54 is fixedly attached to the cap 53 of the bellow52, which can be provided with a guide 55 inside the battery corehousing 11 as can be seen in FIG. 8. The pin 54 is provided with anenlarged frontal conical section 56 that is close or in contact with asloped surface 57 of the member 58 as shown in FIG. 8.

The second component of the actuation mechanism is a normally closedvalve 59. The normally closed valve 59 comprises a valve cap 61, whichis provided with a stem member 62 that passes through a hole that isprovided in the base 64 of the oxygen gas container 18, FIG. 7. Theopposite side of the stem member 62 is provided with the member 58,which is used to provide support for the preloaded compressive spring 65and its bottom surface 57 is sloped as can be seen in FIG. 8 to engagethe surface of the conical section 56 of the actuation mechanism. Anelastomeric gasket 63 is also provided between the surface of the oxygengas container surface 64 and a surface of the valve cap 61. Thecompressive spring 65 is preloaded enough to ensure that in its normallyclosed state, no oxygen gas can escape into the battery core from thepressurized oxygen container 18. The pressurized oxygen gas itself alsoassists in sealing of the valve in its normally closed state.

The Li-Oxygen reserve battery embodiment 50 of FIG. 7 operates asfollows. In normal conditions, the valve 59 is closed and preventsoxygen gas from entering the porous carbon-based O₂ cathode of thebattery core. The reserve battery 50 is therefore in its inactive stateand provides a long shelf life that can significantly exceed themilitary required 20 years. The user may then manually press the cap 53of the bellow 52 in the direction of the arrow 66, FIG. 8. As a result,the bellow 52 begins to deform, allowing the pin 54 to slide forward inthe guide 55, causing the conical section 56 to move forward, therebyengaging the sloped surface 57 of the member 58 and forcing it to beginto move upward as seen in the view of FIG. 8. As a result, the cap 61 islifted from over the elastomeric gasket 63, thereby allowing the oxygengas to begin to flow into the porous carbon-based O₂ cathode section ofthe battery core and activate the reserve battery. When the appliedforce to the cap 53 of the bellow 52 in the direction of the arrow isremoved, the compressed bellow 52 would spring back (which might beassisted by an internal compressive spring that is provided around thepin 54 inside the bellow—not shown), thereby allowing the preloadedcompressive spring 65 and the pressurized oxygen gas to close the valve59 and stop transfer of pressurized gas into porous carbon-based O₂cathode section of the battery core. The battery is thereby reverted toits reserve state and the battery core would stop generating electricalenergy once its present oxygen gas has been consumed.

It is appreciated by those skilled in the art that the cap 53 of thebellow 52, FIG. 8, may also be displaced forward in the direction of thearrow 66 by an externally positioned linear or rotary electrical orpiezoelectric-based or pneumatic or the like actuation device oncommand, for example provided by a system control system, as is wellknown in the art.

It is noted that in the embodiments 30, 40 and 50 of FIGS. 5, 6 and 7,respectively, the activation mechanism bellow is positioned outside ofthe reserve battery housing. Such positioning of the activation devicebellow may then be used to provide a “safety pin” for the reservebattery to protect it against accidental activation, such as during thebattery fabrication and packaging and during the process of installingin the final product. The “safety pin” may in general be positionedbetween the bellow cap (33, 42 and 53 in FIGS. 5, 6 and 8, respectively)and the outer surface of the reserve battery. An example of such abellow actuation preventing “safety pin” as applied to the activationmechanism of the reserve battery embodiment 30 of FIG. 5 is shown in theschematics of FIG. 8A and the top view of FIG. 8B.

In the schematic of FIG. 8A the reserve battery activation mechanism ofthe Lithium-Oxygen reserve battery embodiment 30 of FIG. 5 as mounted onthe top surface 145 (32 in FIG. 5) of the oxygen gas container 146 isshown. As was described for the embodiment of FIG. 5, the bellow 140 (31in FIG. 5) is fixedly attached to the surface 145. The bellow 140 isprovided with a sealing cap 143, which is larger than the cap 33 of theembodiment of FIG. 5. The sliding pin 144 (34 in FIG. 5) with the sharptip is also shown in FIG. 8A. The “safety pin” of the activationmechanism comprises a “U” shaped member 147, which is positioned aroundthe bellow 140 and under the edges 148 of the cap 143 as can be seen inFIG. 8A and the top view of FIG. 8B. It is noted that FIG. 8A is thecross-sectional view C-C of FIG. 8B. The “U” shaped member 147 wouldthen prevent accidental depression of the cap 143 and thereby accidentalactivation of the reserve battery. A pin 149 can also be provided thatpasses through matching holes (not seen in FIG. 8A) through the ends ofthe “U” shaped member 147 as shown in FIG. 8B to prevent the “U” shapedmember 147 from falling off as the reserve battery is handled. With thedescribed “safety pin” assembly, the reserve battery is renderednon-operational. To make the reserve battery operational, the user wouldpull the pin 149 out to allow the “U” shaped member 147 to be pulled outfrom under the cap 143, thereby freeing the bellow 140 to be depressedto rupture the membrane 13 (FIG. 5), thereby activating the reservebattery as was previously described.

The valve 59 configuration may be readily adapted to provide an inertialactivation mechanism that does not rely on rupturing a diaphragm, suchas was described for the Lithium-oxygen reserve battery embodiment 20 ofFIG. 4. Such a Lithium-oxygen reserve battery embodiment 60 is shown inthe cross-sectional schematic of FIG. 9. Such a Lithium-oxygen reservebattery embodiment 60 has two basic advantages over the embodiment 20 ofFIG. 4. The first advantage is that it does not require the supportstructure (23 or 25 in FIG. 4). As a result, it makes the reservebattery fabrication and assembly simpler. Secondly, since thepressurized oxygen gas assists in keeping the valve closed and sealed,the preloaded compressive spring is only required to provide arelatively small force to keep the valve components together before andafter activation.

In the Lithium-Oxygen embodiment 60 of FIG. 9, the inertial activationmechanism comprises a mass member 67, which is movable in the housing 11and which is connected to the valve cap 69 by a connecting member 68that passes through a hole provided in the base of the pressurizedoxygen gas container 18. An elastomeric gasket 71 is provided under thevalve cap 69 and is pressed down by the preloaded compressive spring 72and the pressure of the oxygen gas to ensure that there is no leakage ofthe oxygen gas into the battery core through the provided hole in theoxygen gas container. A support member 73 is fixedly attached to thebottom surface 77 of the pressurized oxygen gas container 18. A slidingmember 74 is then provided that is normally pressed slightly against theside of the valve cap 74 by the preloaded compressive spring 75. Allother components of the Lithium-oxygen reserve battery embodiment 60 aresimilar to that of the embodiment 10 of FIG. 3.

The Li-Oxygen reserve battery embodiment 60 of FIG. 9 operates asfollows. In normal conditions, the preloaded compressive spring 72 andthe pressurized oxygen gas in the container 18 keep the valve closed andprevent oxygen gas from entering the porous carbon-based O₂ cathode ofthe battery core. If the device to which the reserve battery 60 isattached is accelerated in the direction of the arrow 76, theacceleration would act on the inertia of the mass member 67 and theconnecting member 68 and the cap 69, generating an upward dynamic force.The compressive spring 72 is preloaded such that when the accelerationin the direction of the arrow 76 has reached a prescribed threshold,then the generated dynamic force would overcome the spring preload andthe assembly of the mass member 67, connecting member 68 and the cap 69would begin to move upward as viewed in FIG. 9. If the acceleration inthe direction of the arrow 76 is long enough in duration, the cap 69 ismoved up enough to allow the pressurized oxygen gas to begin to flowinto the porous carbon-based O₂ cathode section of the battery core andactivate the reserve battery. Once the cap 69 has moved up, the gapbetween the bottom surface of the cap 69 and the surface 77 of thecontainer 18 is configured to be enough to allow the “locking” member 74to be pushed under the cap 69 and prevent the cap to close the flow ofthe oxygen gas into the battery core once the acceleration in thedirection of the arrow 76 has ceased. Thereby, the reserve battery isactivated and stays activated after the acceleration event, for exampledue to the firing of a munition in which the reserve battery is mounted.If the applied acceleration in the direction of the arrow 76 is belowthe prescribed threshold, for example due to accidental drop of theobject to which the reserve battery 60 is attached, the valve staysclosed and the reserve battery is not activated.

It is appreciated that the Lithium-oxygen reserve battery embodiment 50of FIG. 7 can be activated using a linear or rotary electrical orpiezoelectric-based actuation device such as a solenoid as waspreviously described. However, an external power source is needed at thetime of initial reserve battery activation. This requirement may not bedesirable in some munition applications.

The Lithium-oxygen reserve battery embodiment 70 of FIG. 10 isconfigured to be activated during the munitions firing for a shortperiod of time to activate the reserve battery long enough to generatethe electrical energy needed to operate the electrically actuatedactivation mechanism of the reserve battery as required by the systembeing powered by the reserve battery.

In the Lithium-Oxygen reserve battery embodiment 70 of FIG. 10, thebattery activation mechanism comprises the normally closed valve 59,FIG. 8, and the actuation mechanism 84. The components of the normallyclosed valve 59 are similar to that used in the embodiment of FIG. 8.All other components of the Lithium-oxygen reserve battery embodiment 70are similar to that of the embodiment 10 of FIG. 3.

The actuation mechanism 84 of the Lithium-Oxygen reserve batteryembodiment 70 of FIG. 10 is similar to the one used in the embodiment 50of FIG. 7 (also shown in the blow up view of FIG. 8), and similarlycomprises a metallic bellow 78, such as being formed of the same metalwith which the battery core housing 11 (FIG. 10) is constructed, such asstainless steel. The bellow 78 is fixedly attached to the side surfaceof the battery core housing 11, such as by welding or brazing, and theattachment is tested to ensure that is fully sealed. The bellow 78 isprovided with a sealed cap 79, which may be integral to the bellow 78. Aconnecting member 82 is fixedly attached to the cap 79 of the bellow 78,which is provided with a guide 83 inside the battery core housing 11 ascan be seen in FIG. 10. The connecting member 82 is provided with anenlarged frontal conical section mass member 81 (56 in FIG. 8) that isclose or in contact with the sloped surface 57 of the member 58 of thenormally closed valve 59 as can also be seen in FIG. 8. A preloadedtensile spring 86 may also be provided to ensure that in normalconditions, the mass member does not force the valve 59 to open. It isappreciated by those skilled in the art that instead of the preloadedtensile spring 86, a preloaded compressive spring (not shown) may beplaced inside the bellow 78 to serve the same function.

The Li-Oxygen reserve battery embodiment 70 of FIG. 10 operates asfollows. In normal conditions, as can be seen in the blow-up view ofFIG. 8, the valve 59 is in its closed state and prevents oxygen gas fromentering the porous carbon-based O₂ cathode of the battery core. In thisstate, the biasing forces of the compressively preloaded spring 65 (FIG.8) and the pressure of the oxygen gas ensures that the valve 59 staysclosed. The reserve battery 70 is therefore in its inactive state andprovides a long shelf life that can significantly exceed the militaryrequired 20 years. If the device to which the reserve battery 70 isattached is accelerated in the direction of the arrow 85, theacceleration would act on the inertia of the mass member 81 and theconnecting member 82 and the cap 79, generating a downward dynamic forceas seen in the view of FIG. 10. The tensile spring 86 is preloaded suchthat when the acceleration in the direction of the arrow 85 has reacheda prescribed threshold, then the generated dynamic force would overcomethe spring preload and the assembly of the mass member 81 and theconnecting member 82 and the cap 79 would begin to move down as viewedin FIG. 10. If the acceleration in the direction of the arrow 85 is longenough in duration, the bellow 78 begins to deform, allowing the conicalmass member 81 to move down, thereby engaging the sloped surface 57 ofthe member 58 (FIG. 8) and forcing it to begin to move to the right asseen in the view of FIG. 10. As a result, the cap 61 is lifted from overthe elastomeric gasket 63 (FIG. 8), thereby allowing the oxygen gas tobegin to flow into the porous carbon-based O₂ cathode section of thebattery core and activate the reserve battery. Then once theacceleration in the direction of the arrow 85 has ceased, the massmember 81 is forced to return to its pre-acceleration position shown inFIG. 10 by the preloaded tensile spring 83 and the valve 59 is closedand the flow of oxygen gas into the battery core is stopped.

If the applied acceleration in the direction of the arrow 85 is belowthe prescribed threshold, for example due to accidental drop of theobject to which the reserve battery 70 is attached, the preloading levelof the tensile spring 86 is not overcome, and the mass member 81 dosenot engage the sloped surface 57 of the member 58 and the valve 59 staysclosed.

The Lithium-Oxygen reserve battery embodiment 70 of FIG. 10 is alsoprovided with a linear or rotary electrical or piezoelectric-based orthe like actuation device, such as a solenoid 80, which can be used tosimilarly apply an actuating force to the cap 79 by its linearlydisplacing core 89 to open the valve 59 as was described above to let aninflow of oxygen gas into the battery core on demand. In the presentembodiment 70, the inertial activation in response to a prescribedacceleration profile as was previously described is configured to allowenough oxygen gas into the battery core to power the device electronicsand power control system and to operate the on/off activation actuationdevice, in this case the solenoid 80.

In the Lithium-Oxygen reserve battery embodiment 70 of FIG. 10, theinertial activation in response to a prescribed acceleration profile isconfigured to allow enough oxygen gas into the battery core to power thedevice electronics and power control system and to operate the on/offactivation actuation device, in this case the solenoid 80.Alternatively, the Lithium-Oxygen reserve battery embodiment 70 may bepaired with a capacitor (or supercapacitor) 91, which is charged by theelectrical energy generated by the initial activation of the reservebattery. The electrical energy stored in the capacitor 91 can then beused by the object to which the reserve battery is attached (e.g., a gunfired munition), and to re-activate the reserve battery as needed by theactuator 80. Such a combined Lithium-Oxygen reserve battery andcapacitor (super-capacitor) reserve power sources are hereinafterreferred to as the “Lithium-Oxygen hybrid reserve batteries.”

It is appreciated that the Lithium-oxygen reserve battery embodiment 70of FIG. 10 is configured to be activated during the munitions firing fora short period of time to activate the reserve battery long enough togenerate the electrical energy needed to operate the electricallyactuated activation mechanism of the reserve battery as required by thesystem being powered by the reserve battery. The actuation mechanismshown is the schematic of FIG. 10 is a linear solenoid. However, otherlinear or rotary electrical or piezoelectric-based or the like actuatorsmay also be used for this purpose. In the embodiment 70 of FIG. 10, thelinear solenoid actuation device is shown to be positioned external tothe reserve battery housing. In many munition applications, it is highlydesirable that all components of the reserve battery be inside ahermetically sealed housing. To this end, the reserve battery embodiment70 is modified as described below to house all externally positionedcomponents of the reserve battery inside the hermetically sealed batteryhousing as shown in the embodiment 90 of FIG. 11.

In the Lithium-Oxygen reserve battery embodiment 90 of FIG. 11, thebattery activation mechanism comprises the normally closed valve 59,FIG. 8, and the linear solenoid (or piezoelectric-based actuation)mechanism. The configuration and all the components of the normallyclosed valve 59 are similar to those used in the embodiment of FIG. 8.All other components of the Lithium-oxygen reserve battery embodiment 70are similar to that of the embodiment 10 of FIG. 3.

The actuation mechanism of the Lithium-Oxygen reserve battery embodiment90 of FIG. 11 comprises a metallic bellow 92, which can be formed of thesame metal with which the battery core housing 11 is constructed, suchas stainless steel. The bellow 92 is fixedly attached to the sidesurface 93 of the battery core housing 11, such as by welding orbrazing, and the attachment is tested to ensure that is fully sealed.The bellow 92 is provided with a sealed cap 94, which may be integral tothe bellow 92. A linear solenoid actuator 95 (or a piezoelectric or thelike electrically actuated device) is positioned inside the bellow andfixed to the cap 94 as can be seen in FIG. 11. In FIG. 11, the terminals101 indicate the powering terminals of the solenoid 95, which are passedthrough the electrical insulations (not shown) provided in the cap 94.The actuating core 96 of the solenoid 95 is then attached to a conicalsection shaped mass member 97. The mass member 97 is fixedly attachedand sealed to the bellow 92. The conical section mass member 97 (56 inFIG. 8) is positioned close or in contact with the sloped surface 98 (57in FIG. 8) of the member 99 (58 in FIG. 8) of the normally closed valve59 as can also be seen in FIG. 11. The solenoid 95 is provided with aproper return spring so that while it is not energized, the mass member97 is at the position shown in FIG. 11 and does not force the valve 59to open. The cap 94 may be provided with a small hole to prevent the air(gas) trapped inside the below 92 from resisting its extension.

The Li-Oxygen reserve battery embodiment 90 of FIG. 11 operates asfollows. In normal conditions, the valve 59 is in its closed state andprevents oxygen gas from entering the porous carbon-based O₂ cathode ofthe battery core. In this state, the biasing forces of the compressivelypreloaded spring 102 (65 in FIG. 8) and the pressure of the oxygen gasensures that the valve 59 stays closed. The Li-Oxygen reserve battery 90is therefore in its inactive state and provides a long shelf life thatcan significantly exceed the military required 20 years. If the deviceto which the reserve battery 90 is attached is accelerated in thedirection of the arrow 104, the acceleration would act on the inertia ofthe mass member 97 and the solenoid core 96, generating a downwarddynamic force as seen in the view of FIG. 11. The biasing spring in thesolenoid 96 (not shown) is preloaded such that when the acceleration inthe direction of the arrow 104 has reached a prescribed threshold, thenthe generated dynamic force would overcome the spring preload and theassembly of the mass member 97 and the solenoid core 96 would begin tomove down as viewed in FIG. 11. It is appreciated that a preloadedtensile spring (not shown) may instead be provided around the solenoidcore 96 (similar to preloaded tensile spring 86 in FIG. 10) to performthe same function. If the acceleration in the direction of the arrow 104is long enough in duration, the bellow 92 begins to deform, allowing theconical mass member 97 to move down, thereby engaging the sloped surface98 of the member 99 (58 in FIG. 8) and forcing it to begin to move tothe right as seen in the view of FIG. 11. As a result, the cap 106 (61in FIG. 8) is lifted from over the elastomeric gasket 103 (63 in FIG.8), thereby allowing the oxygen gas to begin to flow into the porouscarbon-based O₂ cathode section of the battery core and activate thereserve battery. Then once the acceleration in the direction of thearrow 104 has ceased, the mass member 97 is forced to return to itspre-acceleration position shown in FIG. 11 by the preloaded biasingspring of the solenoid 95, the extended bellow 92, preloaded compressivespring 102 and the oxygen gas pressure, thereby closing the valve 59 andstopping the flow of oxygen gas into the battery core.

If the applied acceleration in the direction of the arrow 104 is belowthe prescribed threshold, for example due to accidental drop of theobject to which the reserve battery 90 is attached, the preloading levelof the aforementioned biasing tensile springs are not overcome, and themass member 97 assembly dose not engage the sloped surface 98 of themember 99 and the valve 59 stays closed.

It is appreciated by those skilled in the art that the linear solenoidactuator 95 (or other similar linear or rotary actuators) may be of alatching type. In such a case, at any point in time following initialinertial activation, the battery may be activated and made to remainactivated without requiring power to be continuously be applied to theactuator 95. The solenoid may also be actuated less than the distancethat activates the latching mechanism, thereby providing the capabilityto reactivate the reserve battery several times until it is desired tostay permanently activated, at which time the solenoid is actuated tothe point of activating its latching mechanism.

It is also appreciated by those skilled in the art that all electronicand drive components and the capacitor 107 that are used to sense thereserve battery embodiment 90 power level and activate the battery asneeded may also be integrated inside the reserve battery housing 11.Such self-contained Li-Oxygen reserve batteries would greatly simplifytheir integration into various devices such as gun-fired munitions.

In the Li-Oxygen reserve battery embodiment 90, the inertial activationin response to the prescribed acceleration profile is configured toallow enough oxygen gas into the battery core to power the deviceelectronics and power control system and to operate the solenoid 95 toopen and close the valve 59 when needed to supply the requiredelectrical energy. The reserve battery embodiment 90 may also beprovided with a capacitor or super-capacitor 107 as was shown in FIG. 10to form a “Lithium-Oxygen hybrid reserve battery”.

In the Lithium-Oxygen reserve battery embodiment 90 of FIG. 11, similarto the embodiment 70 of FIG. 10, the inertial activation in response toa prescribed acceleration profile is configured to allow enough oxygengas into the battery core to power the device electronics and powercontrol system and to operate the on/off activation actuation device, inthis case the solenoid 95. Alternatively, the Lithium-Oxygen reservebattery embodiment 90 may be paired with a capacitor (or supercapacitor)107, which is charged by the electrical energy generated by the initialactivation of the reserve battery. The electrical energy stored in thecapacitor 107 can then be used by the object to which the reservebattery is attached (e.g., a gun fired munition), and to re-activate thereserve battery as needed by the actuator 95. Such a combinedLithium-Oxygen reserve battery and capacitor (super-capacitor) reservepower source forms a previously described “Lithium-Oxygen hybrid reservebattery”.

It is appreciated by those skilled in the art that such “Lithium-Oxygenhybrid reserve batteries” are particularly advantageous for use inapplications in which they are required to provide low power for longperiods of times and only occasionally have to provide high power,usually for relatively short periods of time. In such applications, thereserve battery only needs to be activated for very short periods oftimes to charge the capacitor and have the capacitor supply the lowpower to usually low power electronics for hours and sometimes for daysuntil either high power is required to be provided or when the capacitorpower is low and it needs to be recharged, at which time the capacitorsupplies power to the activation actuator, FIGS. 10 and 11.

In one embodiment of the present “Lithium-Oxygen hybrid reservebatteries”, a controller/processor, such as an electronic controlcircuit 107 a can be provided to detect the voltage level of the hybridreserve battery electrical energy storage capacitor (e.g., 91 in FIG.10) and energize the battery activation actuator (80 in FIG. 10) for aprescribed amount of time to allow a prescribed amount of oxygen gas toflow into the battery core for its activation. In addition, theelectronic control circuit may be provided with a microprocessor 107 band memory 107 c so that it could be programmed to provide a prescribedpower level based on a received sensory input and/or planned profile.The control circuit electrically connecting the capacitor (energystorage device) to the terminals 101 of the solenoid 95 (actuationdevice).

It is also appreciated by those skilled in the art that theLithium-Oxygen reserve battery embodiment 90 may also be activateddirectly by energizing the solenoid 95 in non-shock loading activationapplications.

The Lithium-oxygen reserve battery embodiment 90 of FIG. 11 isconfigured to be activated either during the munitions firing for ashort period of time and then by the integrated actuation device ordirectly by the integrated actuation device, in this case the linearsolenoid 95. The Lithium-oxygen reserve battery embodiment 90 may alsobe constructed without the electrical actuator as shown in the schematicof FIG. 12 (indicated as the embodiment 100) and instead be providedwith at least a pair of bosses 108 with (interior or exterior) threads109 on the outside surface of the battery housing or those 110 withinternal threads, for the used to attach the desired actuation device(linear or screw type rotary electrical or piezoelectric-based linearactuator or the like). In both options, the bosses are fixedly attachedto the battery housing surface, such as by welding or brazing or thelike and fully sealed to keep the battery core hermetically sealed forlong shelf life. The Lithium-oxygen reserve battery embodiment 100operates as was previously described for the reserve battery embodiment90 of FIG. 11.

In the schematic of FIG. 13A, the blow-up view “B”, FIG. 12, showing thevalve 59 and the actuating conical mass section 97 and the bellow 92 isredrawn. In an alternative configuration, the valve 59 may be replacedwith the configuration shown in the embodiment 60 of FIG. 9. With thereplaced valve, the blow-up view “B” would then become as shown in FIG.13B.

Then in the normal conditions, as was described for the embodiment ofFIG. 9, the preloaded compressive spring 115 and the pressurized oxygengas in the container 18 keep the valve closed and prevent oxygen gasfrom entering the porous carbon-based O₂ cathode of the battery core,FIG. 12. Then if the device to which the reserve battery 100 is attachedis accelerated in the direction of the arrow 112, the acceleration wouldact on the inertia of the mass member 97, generating a downward dynamicforce. The compressive spring 115 is preloaded such that when theacceleration in the direction of the arrow 112 has reached a prescribedthreshold, then the generated dynamic force would overcome the springpreload and the mass member 97 begin to move downward as viewed in FIG.12. Here, the spring rate of the metal bellow is considered to benegligible, otherwise it must also be considered. If the acceleration inthe direction of the arrow 112 is long enough in duration, the cap 116is moved to the right enough to allow the pressurized oxygen gas tobegin to flow into the porous carbon-based O₂ cathode section of thebattery core and activate the reserve battery. Once the cap 116 hasmoved to the right, the gap between the bottom surface of the cap 116and the surface 119 of the container 18 is configured to be enough toallow the “locking” member 121 to be pushed under the cap 116 andprevent the cap to close the flow of the oxygen gas into the batterycore once the acceleration in the direction of the arrow 112 has ceased.Thereby, the reserve battery is activated and stays activated after theacceleration event, for example due to the firing of a munition in whichthe reserve battery is mounted. If the applied acceleration in thedirection of the arrow 112 is below the prescribed threshold, forexample due to accidental drop of the object to which the reservebattery 100 is attached, the valve stays closed and the reserve batteryis not activated.

In an alternative configuration of FIG. 13B, once the valve (59 in FIG.12) is opened due to the prescribed acceleration event, the valve staysopen and the reserve battery 100 stays activated from then on. On theother hand, the valve configuration shown in FIG. 12 and its blow-upview of FIG. 13A provides a reserve battery that requires activation ofits electrical actuation device (e.g., a linear electrical solenoid) toopen the valve 59 to reactivate the reserve battery after its initialinertial (or direct solenoid operated electrical) activation. In thisembodiment, to keep the battery permanently activated after cycles ofactivation/deactivation, the actuation mechanism needs to be keptenergized. To avoid the waste of electrical energy to keep the actuationdevice energized, the modification shown in the blow-up schematic ofFIG. 13C is made to the activation mechanism of the reserve battery.

In the activation mechanism of FIG. 13C, the same valve 59 of theembodiment 100 of FIG. 12 is used. The conical section mass member 120(97 in FIG. 13B) is similarly fixedly attached to the bellow 123 (92 inFIG. 13B). The conical section mass member 120 is also positioned closeor in contact with the sloped surface 124 of the member 125 (113 in FIG.13B) of the normally closed valve 59 as can also be seen in FIG. 13B.The actuation mechanism that is provided for the reserve batteryactivation (for example, the linear solenoid 95 of FIG. 11 or otherlinear or rotary electrical actuator or the like) is provided with aproper return spring so that while it is not energized, the mass member120 is at the position shown in FIG. 13C and does not force the valve 59to open.

The mass member 120 is also provided with a link member 127, which isattached to the mass member 120 by a pin joint 128. The link member 127is provided by a preloaded compressive spring 129, which is attached tothe mass member 129 by the pin joint 131 and is biased to rotate thelink member 127 in the clockwise direction as viewed in FIG. 13C andmostly rest against the surface 124 of the member 125.

Then in the normal conditions, as was described for the embodiment ofFIG. 9, the preloaded compressive spring 115 (FIG. 13B) and thepressurized oxygen gas in the container 18 keep the valve closed andprevent oxygen gas from entering the porous carbon-based O₂ cathode ofthe battery core, FIG. 12. Then if the device to which the reservebattery 100 is attached is accelerated in the direction of the arrow112, the acceleration would act on the inertia of the mass member 120,FIG. 13C, generating a downward dynamic force. The compressive spring(115 in FIG. 13b ) of the valve 59 is preloaded such that when theacceleration in the direction of the arrow 112 has reached a prescribedthreshold, then the generated dynamic force would overcome the springpreload and the mass member 120 begins to move downward as viewed inFIG. 13C. Here, the spring rate of the metal bellow is considered to benegligible, otherwise it must also be considered. If the acceleration inthe direction of the arrow 112 is long enough in duration, the cap 126is moved to the right, allowing the pressurized oxygen gas to begin toflow into the porous carbon-based O₂ cathode section of the battery coreand activate the reserve battery. It is noted that the actuation deviceof FIG. 13C is configured such that the above prescribed accelerationprofiles would not move the mass member 120 down enough along thesurface 124 to have the tip 132 of the link member 127 to pass the tip133 of the member 125 as can be seen in FIG. 13C.

The Lithium-oxygen reserve battery embodiment 100 of FIG. 12 isconfigured to be activated either during the munitions firing for ashort period of time and then by the integrated actuation device (suchas the linear actuator 95 as shown in FIG. 11) or directly by theintegrated actuation device 95. The Lithium-oxygen reserve batteryembodiment 100 may then be activated and deactivated on command by theindicated integrated actuation device. However, during each activationprocess, the integrated actuation device of FIG. 13C advances the massmember 120 down along the surface 124 such that the tip 132 of the linkmember 127 would not pass the tip 133 of the member 125, so that theintegrated actuation device could be commanded to bring the mass member120 back to its position shown in FIG. 13C, thereby closing the flow ofoxygen gas into the battery core and reverting the battery to itsreserve state.

However, at any moment, the integrated actuation device can be used todisplace the mass member down enough so that the tip 132 of the linkmember 127 would clear the tip 133 of the member 125, thereby the linkmember 127 would rotate in the clockwise direction until it is stoppedby the stop member 135 of the mass member 120. As a result, once theintegrated actuation device is de-energized, the link 132 engages thelower surface 136 of the member 125 and prevents the mass member 120from returning to its position shown in FIG. 13C. In the meanwhile, theopened valve 59 would stay open and the oxygen gas would continueflowing into the reserve battery core.

The Lithium-oxygen reserve battery embodiment 10 of FIG. 3 was shown tobe configured to activate when subjected to a prescribed accelerationprofile in the direction of the arrow 22. The reserve battery embodiment10 may, however, be modified so that it could be activated by electricalinitiation of a pyrotechnic charge, i.e., using an electrical initiator.Such a Lithium-oxygen reserve battery embodiment 130 is shown in thecross-sectional schematic of FIG. 14.

In the Lithium-oxygen reserve battery embodiment 130 of FIG. 14, theactivation mechanism comprises a metallic bellow 137 that is fixedlyattached to the surface 21 of the pressurized oxygen container 18, suchas by welding or brazing. An end member 138 is also attached to theother end of the bellow, such as by welding or brazing. The attachmentsof the bellow to the surface 21 and the end member 138 must be sealedand the bellow 137 and end member 138 can be formed from the samematerial as the container 18, such as stainless steel. An electricallyinitiated gas generating pyrotechnic device 141 is provided inside thesealed bellow 137. Initiator service wires 141 are indicated by thenumeral 142 in FIG. 14.

The common wall 19 between the container 18 and the battery core (insidehousing 11) is provided with a relatively small opening 14 into thebattery core, which is normally sealed by a metallic diaphragm 13. Ingeneral, the housings 11 and 18 are made with stainless steel and thediaphragm 13 is also a thin stainless sheet that is welded to the wall19. The end member 138 is provided with a sharp cutting member 139,which is positioned above the hole 14.

The Li-Oxygen reserve battery embodiment 130 operates as follows. Innormal conditions, the diaphragm 13 prevents oxygen gas from enteringthe porous carbon-based O₂ cathode of the battery core. Then if theelectrical gas generating pyrotechnic device 141 is initiated, thepressure due to the generated gas would extend the bellow 137, therebycausing the end member 138 to move down and for the sharp cutting member139 to reach and rupture the diaphragm 13, thereby allowing the oxygengas to begin to flow into the porous carbon-based O₂ cathode section ofthe battery core and activate the reserve battery.

It is appreciated by those skilled in the art that the activationmechanisms such as the externally actuated manual or powered actuationactivation mechanisms of the embodiments of FIGS. 5, 6, 7, 10, 11 and 12may be configured with other types of mechanisms and powered actuatorsbut to perform the same intended functions. The mechanisms and theiractuation devices shown and described are primarily intended to describethe basic methods of activating the present Lithium-Oxygen reservebatteries and examples of mechanisms that can be used to activate themfor continuous use or for multiple activation/deactivation. For example,the activation mechanism of the embodiment 50 of FIG. 7 may be readilymodified for manual operation as shown in the embodiment 150 of FIG. 15or by externally powered actuation devices as described below.

In the Li-Oxygen reserve battery embodiment 150 of FIG. 15, the valveassembly 59, FIG. 7, is still used and may be positioned more centrallyas shown in FIG. 15. However, since its sloped section 57 is no longerneeded, it is eliminated as can be seen in the schematic of FIG. 15. Thebellow-based actuation mechanism of the embodiment 50 of FIG. 7 is thenmodified and repositioned as follows. The mechanism bellow 155 issimilarly attached to the outer surface of the oxygen container 18, suchas by welding or brazing. The bellow 155 is then provided with a cap156, which seals the bellow 155 and is attached to it, such as bywelding or brazing. The guide 153 is similarly attached to the interiorsurface of the container 18 against the bellow 155. A pin 151 isprovided as shown in FIG. 15, which can freely slide in the guide 153and is fixedly attached to the cap 156 on one end and to the valveassembly 59 cap 154 on the other end. A ring or the like member 152 isalso fixedly attached to the cap 156 for manual activation of thereserve battery.

The Li-Oxygen reserve battery embodiment 150 of FIG. 15 operates asfollows. In normal conditions, the valve 59 is closed and preventsoxygen gas from entering the porous carbon-based O₂ cathode of thebattery core. The reserve battery 150 is therefore in its inactive stateand provides a long shelf life that can significantly exceed themilitary required 20 years. The user may then manually pull the ring152, thereby pulling the pin 151 up and lifting the cap 154 from overthe elastomeric sealing gasket (63 in FIG. 7), thereby allowing theoxygen gas to begin to flow into the porous carbon-based O₂ cathodesection of the battery core and activate the reserve battery. Then whenthe user releases the ring 152, the extended bellow 155 would tend tospring back and assisted with the compressed oxygen gas pressure actingon the cap 154 would close the valve 59 and stop transfer of pressurizedgas into porous carbon-based O₂ cathode section of the battery core. Thebattery is thereby reverted to its reserve state and the battery corewould stop generating electrical energy once its present oxygen gas hasbeen consumed.

It is appreciated by those skilled in the art that the cap 156 of thebellow 155, FIG. 15, may also be displaced up and down, as viewed inFIG. 15, by an externally positioned linear or rotary electrical orpiezoelectric-based or pneumatic or the like actuation device as wasdescribed, for example, for the embodiment 70 of FIG. 10, on commandsprovided by the system controls as is well known in the art.

The Lithium-Oxygen reserve battery embodiments 10 and 20 of FIGS. 3 and4, respectively, are configured to be activated when the device to whichthey are attached is subjected to a prescribed acceleration profile,such as firing of a gun. In many munition applications, such as inrockets, the reserve battery is required to be activated at prescribedaccelerations that are low in magnitude, for example in tens of Gsrather than thousands in the case of gun-fired munitions, and lasts afew tens of milliseconds. In such applications, the activationmechanisms of the embodiments 10 and 20 of FIGS. 3 and 4, respectively,may not be suitable since they may require very large inertial mass (16and 27 in FIGS. 3 and 4, respectively) to make them capable of rupturingthe provided diaphragms to activate the reserve battery. The activationmechanism of the Lithium-Oxygen reserve battery embodiment 160 of FIG.16 is configured for such relatively low G prescribed firingaccelerations or the like applications.

In the schematic of FIG. 16, all other components of the reserve batteryare similar to that of the embodiment 10 of FIG. 3, except for itsinertial activation mechanism. As can be seen in FIG. 16, theLithium-Oxygen reserve battery embodiment 160 is provided with anactivation mechanism that comprises a link 161, which is attached to thesurface 163 of the pressurized oxygen container by the rotary joint 162.In normal conditions the link 161 is in the configuration shown in FIG.16, in which the tip 174 of the link rests on provided “step” on the tip171 of the inertial mass 170. In this configuration, the inertial mass170 is being pushed against the tip 174 of the link 161 by the preloadedcompressive spring 173. The preloaded compressive spring 173 ispositioned between the inertial mass 170 and the support 172, which isfixedly attached to the surface 163 of the pressurized oxygen container.The link 161 is also held in its position shown in FIG. 16 by thepreloaded compressive spring 167, which is attached to the link 161 bythe pin joint 168 on one end and to the inside of the pressurized oxygencontainer by the pin joint 169 on the other end. The link 161 is alsoprovided with a sharp cutting member 164, which in the normal conditionof FIG. 16 is positioned above the hole 165 in the side 163 of thepressurized oxygen container that is covered by the diaphragm 166, whichcan be metallic and attached to the container surface by welding orbrazing.

The Li-Oxygen reserve battery embodiment 160 of FIG. 16 operates asfollows. In normal conditions, the diaphragm 166 prevents oxygen gasfrom entering the porous carbon-based O₂ cathode of the battery core. Ifthe device to which the reserve battery 160 is attached is acceleratedin the direction of the arrow 175, the acceleration would act on theinertial mass 170, generating a downward dynamic force. The compressivespring 173 is preloaded such that when the acceleration in the directionof the arrow 175 has reached a prescribed threshold, then the generateddynamic force would overcome the spring preload and the inertial mass170 would begin to move downward as viewed in FIG. 16. If theacceleration in the direction of the arrow 175 is long enough induration, the inertial mass 170 moves down enough so that the tip 171clears the tip 174 of the link 161. The preloaded compressive spring 167will then accelerate the link 161 in rotation in the clockwise directionuntil the sharp cutting member 164 strikes the diaphragm 166 and causesit to rupture, thereby allowing the oxygen gas to begin to flow into theporous carbon-based O₂ cathode section of the battery core and activatethe reserve battery. If the duration of the applied acceleration in thedirection of the arrow 175 is very short, for example due to accidentaldrop of the object to which the reserve battery 160 is attached, theinertial mass 170 and spring 173 system is configured such that the link161 is not released and thereby the reserve battery is not activated.

In various embodiments disclosed above, for any components described asbeing movable within the porous carbon-based O₂ cathode, the porouscarbon-based O₂ cathode is configured to permit such movement, such ashaving a corresponding void.

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

What is claimed is:
 1. A metal-gas battery comprising: a battery corecomprising: a metal anode; a non-aqueous electrolyte; a porous cathode;and terminals for providing electrical power from the battery core; acontainer configured to hold a pressurized gas; and a member configuredto be movable from a non-activated position in which the pressurized gasin the container is sealed from entering the porous cathode and anactivated position in which the pressurized gas flows into the porouscathode to activate the battery core.
 2. The metal-gas battery of claim1, wherein the battery core comprises a housing for hermetically sealingthe metal anode, non-aqueous electrolyte and porous cathode therein. 3.The metal-gas battery of claim 2, wherein: the housing having a holeproviding fluid communication between the housing and the container; adiaphragm sealingly closing the hole; and the member has a portionconfigured to rupture the diaphragm when moved to the activatedposition; wherein the member is biased in the non-activated position. 4.The metal-gas battery of claim 3, wherein the member is configured tomove to the activated position when the member experiences apredetermined acceleration profile.
 5. The metal-gas battery of claim 3,wherein the member is configured to move to the activated position whenthe member is moved to the activated position by an applied force. 6.The metal-gas battery of claim 5, wherein: the member includes anextending portion; and a bellows sealingly covers the extended portion,the bellows at least partially biasing the member in the non-activatedposition.
 7. The metal-gas battery of claim 1, further comprising anactivation device configured to move the member to the activatedposition, the activation device providing a force to move the member tothe activated position.
 8. The metal-gas battery of claim 7, furthercomprising an energy storage device configured to receive at least apartial amount of energy generated by the battery core after the memberis moved to the activated state, the energy storage device at leastpartially providing the received energy to operate the actuation deviceto selectively move the member between the non-actuated and actuatedpositions.
 9. The metal-gas battery of claim 8, wherein the energystorage device is under the control of a controller.
 10. The metal-gasbattery of claim 2, wherein: the housing having a hole providing fluidcommunication between the housing and the container; the member has afirst portion configured to seal the hole when in the non-activatedposition, the member having a second portion connected to the firstportion through the hole; a spring for biasing the second portion awayfrom the hole such that the first portion sealingly engages the holewhen the member is in the non-activated position.
 11. The metal-gasbattery of claim 10, wherein at least the second portion and spring areconfigured to move the member to the activated position when the memberexperiences a predetermined acceleration profile.
 12. The metal-gasbattery of claim 11, further comprising an other member configured to bemovable when the member moves into the activated position to prevent themember from moving back into the non-activated position.
 13. Themetal-gas battery of claim 1, further comprising a spring for biasingthe member in the non-activated position.
 14. The metal-gas battery ofclaim 1, wherein the member is provided at least partially in thecontainer.
 15. The metal-gas battery of claim 1, wherein the member isprovided at least partially in the porous cathode.
 16. The metal-gasbattery of claim 1, wherein the member moves in translation from thenon-activated position to the activated position.
 17. The metal-gasbattery of claim 1, wherein the member moves in rotation from thenon-activated position to the activated position.
 18. The metal-gasbattery of claim 1, further comprising an obstruction member forobstructing the movement of the member from the non-activated positionto the activated position, wherein the obstructing member is configuredto be manually removed to allow movement of the member from thenon-activated position to the activated position.
 19. The metal-gasbattery of claim 1, further comprising an other member configured toprevent movement of the member to the non-activated position afterachieving the activated position.
 20. The metal gas battery of claim 1,wherein the member is configured to selectively move from the activatedposition to the non-activated position.
 21. The metal-gas battery ofclaim 1, wherein the metal anode is Lithium.
 22. The metal-gas batteryof claim 1, wherein the pressurized gas is Oxygen or a gas containingOxygen.
 23. The metal-gas battery of claim 22, wherein the porouscathode is a porous Carbon-based cathode.